BEST by a mile! Value for Money!
By far the best registrars I've used. The first domain I registered was over 7-8 years ago and I've used many registrars, but I can honestly say NameCheap is the best by a mile.
I've only used customer service for very minor problems - sending emails to them... but they responded very fast each time and solved the problems straight away. I couldn't comment on how their phone CS is because I've never had to use it.
OK, the only downside is the user interface... at first it looks like a control panel on an aircraft... however you get used to it. The features are great and the fact they give away free whois guard a big bonus. Everytime I've registered a domain, its been slick and simple. No hassles at all.
Pricing isn't the cheapest, but for what they offer I'd go with them than anyone else. $8.88 for a .com isn't bad anyway. Even if someone charges a dollar or two less I'd still opt for Namecheap. Well done NameCheap.